News tagged with radiocarbon

A Toronto-based company has been convicted of selling illegal ivory in the first case to use a technique for dating ivory developed by a scientist at the Lamont-Doherty Earth Observatory in collaboration ...

A partial human skull unearthed in 2008 in northern Israel may hold some clues as to when and where humans and Neanderthals might have interbred. The key to addressing this, as well as other important issues, ...

Using radiocarbon dating on metal found in Gothic cathedrals, an interdisciplinary team has shown, for the first time through absolute dating, that iron was used to reinforce stone from the construction phase. ...

In Jeju, a place emerging as a world-famous vacation spot with natural tourism resources, a recent study revealed a volcanic eruption occurred on the island. The Korea Institute of Geoscience and Mineral ...

(Phys.org) —A handful of tree ring samples stored in an old cigar box have shed unexpected light on the ancient world, thanks to research by archaeologist Sturt Manning and collaborators at Cornell, Arizona, ...

(Phys.org) —An earthquake in Old Jerusalem might be behind the famous image of the Shroud of Turin, says a group of researchers led by Alberto Carpinteri of the Politecnico di Torino in Italy in an article published in ...

(Phys.org) —Flinders University researcher Amy Macken has discovered the age of sedimentary layers in the Naracoorte Caves using a cutting-edge computer modelling technique that has never before been used ...

(Phys.org) —The heat is on, at least in the Arctic. Average summer temperatures in the Eastern Canadian Arctic during the last 100 years are higher now than during any century in the past 44,000 years and ...

Matthew Hill has identified countless bones found by farmers, fishermen, rock hounds and heavy equipment operators. Most of the remains turn out to be deer, bison, horse or cow bones, or simply odd looking ...

For the first time, a team of scientists and archaeologists has been able to set a robust timeline for the first eight dynastic rulers of Egypt. Until now there have been no verifiable chronological records for this period ...

(Phys.org) —An international team of researchers led by Oxford University has new dating evidence indicating when the earliest fully modern humans arrived in the Near East, the region known as the Middle ...

Carbon-14

Carbon-14, 14C, or radiocarbon, is a radioactive isotope of carbon discovered on February 27, 1940, by Martin Kamen and Sam Ruben at the University of California Radiation Laboratory in Berkeley, though its existence had been suggested already in 1934 by Franz Kurie. Its nucleus contains 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method to date archaeological, geological, and hydrogeological samples.

There are three naturally occurring isotopes of carbon on Earth: 99% of the carbon is carbon-12, 1% is carbon-13, and carbon-14 occurs in trace amounts, e.g. making up as much as 1 part per trillion (0.0000000001%) of the carbon in the atmosphere. The half-life of carbon-14 is 5,730±40 years. It decays into nitrogen-14 through beta decay. The activity of the modern radiocarbon standard is about 14 disintegrations per minute (dpm) per gram carbon.

The atomic mass of carbon-14 is about 14.003241 amu. The different isotopes of carbon do not differ appreciably in their chemical properties. This is used in chemical research in a technique called carbon labeling: some carbon-12 atoms of a given compound are replaced with carbon-14 atoms (or some carbon-13 atoms) in order to trace them along chemical reactions involving the given compound.